In various medical applications, a computer-generated reconstruction of body parts or organs is displayed to a user. For example, U.S. Pat. No. 6,456,867, whose disclosure is incorporated herein by reference, describes a method of reconstructing a map of a volume. The method includes determining coordinates of locations on a surface of the volume, and generating a grid of points defining a reconstruction surface in 3-D space in proximity to the determined locations. For each of the points on the grid, a respective vector is defined dependent on a displacement between one or more of the points on the grid and one or more of the locations. The reconstruction surface is then adjusted by moving substantially each of the points on the grid responsive to the respective vector, so that the reconstruction surface is deformed to resemble the configuration of the surface.
In some applications, images from multiple modalities, or imaging sources, are fitted with one another and presented. For example, U.S. Pat. No. 5,568,384, whose disclosure is incorporated herein by reference, describes a method for synthesizing 3-D multimodality image sets into a single composite image. Surfaces are initially extracted from two or more different images to be matched using semi-automatic segmentation techniques. The surfaces are represented as contours with common features to be matched. A distance transformation is performed for one surface image, and a cost function for the matching process is developed using the distance image. The geometric transformation includes three-dimensional translation, rotation and scaling to accommodate images of different position, orientation and size. The matching process involves searching the multi-parameter space and adjusting a surface or surfaces to find the best fit among them, which minimizes the cost function.